Calorimetric observations of the transition of spherical to rodlike micelles with solubilized organic additives

Lindemuth, Paul M.; Bertrand, Gary L.

doi:10.1021/j100131a055

Cited by 96 publications

(85 citation statements)

References 2 publications

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“…At the same time, IMP contains an amine group as head group and IBF has a carboxylic acid group. It is a well known fact that an amine is more hydrophilic than a carboxylic acid [14]. These two factors oppose each other and, in our drugs, the first factor dominates and the cmc of IMP is lower than that of IBF.…”

Section: Resultsmentioning

confidence: 78%

Effect of Asymmetric Dimeric Zwitterionic Surfactants on Micellization Behavior of Amphiphilic Drugs

et al. 2015

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The micellization process in mixtures of amphiphilic drugs and asymmetric dimeric zwitterionic surfactants have been investigated tensiometrically. The drugs used are from two families: imipramine hydrochloride (IMP)-a tricyclic antidepressant and ibuprofen (IBF)-a nonsteroidal antiinflammatory drug, whereas zwitterionic dimeric surfactants are heterogemini surfactants that contain quaternary ammonium and phosphate groups as heads. The results show that the cmc of drug-surfactant mixtures decreases with the increase in stoichiometric mole fraction of surfactants (a 1 ), suggesting attractive interaction among the two components. This is supported by the values of cmc id (critical micelle concentration values for ideal mixing) which are always greater than experimental cmc values. Also, the decrease in magnitude is more in IBF-dimeric surfactant mixed systems than in IMP-dimeric surfactant mixed systems. Micellar mole fraction values, obtained using Rubingh's (X m 1 ) and Motomura's (X m 1 ) models, are lower than the micellar mole fraction for ideal mixing (X id 1 ). The micellar interaction parameter (b m ) follows the order: 8(. The results are explained on the basis of difference in tail lengths. Interfacial mole fraction (X r 1 ) values, evaluated using Rosen's model, are higher than X m 1 values for IMP-10(-)-2-16(?) and IMP-10(-)-2-14(?) systems while for all other systems (except 8(-)-2-14(?)) the values are smaller than X m 1 . The interaction parameter at the interface (b r ) is negative and b m av values are greater than b r av in magnitude. All the results indicate that the dimeric surfactants are mostly in cationic form.

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Section: Resultsmentioning

confidence: 78%

Effect of Asymmetric Dimeric Zwitterionic Surfactants on Micellization Behavior of Amphiphilic Drugs

et al. 2015

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“…Since Stigter (5) reported the phenomenon of micellar shape transition, the possibilities of changes of shape or size have continually been proposed experimentally (6,7), mathematically (8), and theoretically (9). Examination of packing conditions of the micelles shows that the critical conditions for formation of different micellar structures are the following (8,10): (i) spherical micelles, v/al ≤ 1/3; (ii) globular or cylindrical micelles, 1/3 ≤ v/al ≤ 1/2; (iii) vesicles or bilayers, 1/2 ≤ v/al ≤ 1; and (iv) inverted structures, v/al ≥ 1, where v is the volume of the surfactant's hydrocarbon tail, a is the cross-sectional area per head group, and l is the length of the fully extended hydrocarbon tail, obtainable from Tanford's formula (11).…”

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confidence: 99%

Effects of various hydrocarbons on micellar growth

Kumar

David

Kabir-ud-Din

1997

J Americ Oil Chem Soc

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The effect of aliphatic and aromatic hydrocarbons on surfactant micellar growth has been investigated by viscosity measurements at 40°C. Aqueous and aqueous KBr (0.1 M) solutions of 0.1 M cetylpyridinium bromide (CPB) showed that the viscosity behavior changed substantially in the presence of KBr. This is attributed to favorable conditions produced by KBr that assist micellar growth by addition of hydrocarbons. Reasons for the effectiveness of the solubilized hydrocarbons are suggested and supported by theoretical arguments. The causes of viscosity decrease at higher aromatic hydrocarbon concentrations are also explained. Micellar growth with soluble aromatic/aliphatic hydrocarbons could also be initiated if a moderate salt concentration is present in CPB micellar solutions. The chainlength, solubilization site, and molar volume of the soluble hydrocarbons all affect the bulk viscosity of the solution. Such surfactant and hydrocarbon combinations may find use in micellar-enhanced ultrafiltration of benzene and its derivatives, but it should be kept in mind that micellar shape may change and be more curved at higher benzene derivative concentrations. JAOCS 74, 797-801 (1997).

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“…[Ninhydrin] ϭ 1.0 ϫ 10 dm hydrin is a polar molecule with a -electron cloud around it, which has the likelihood of coming closer to the cationic micellar surface [16]. Histidine, being in the zwitterionic form with its negatively charged carboxylate and protonated amino groups, binds and gets accumulated in the Stern layer of the cationic CTAB micelles (the effect will be slightly diminished in the histidine methyl ester due to the presence of an ester group).…”

Section: ϫ2 ϫ3mentioning

confidence: 99%

Kinetics of interaction of Histidine and Histidine Methyl Ester with Ninhydrin in micellar media

Kabir-ud-Din

Rafiquee

Akram

et al. 1999

Int. J. Chem. Kinet.

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Kinetics of the interaction of histidine and histidine methyl ester with ninhydrin under varying concentrations of reactants, anionic (sodium dodecyl sulphate, SDS), cationic (cetyltrimethylammonium bromide, CTAB) and non-ionic (Triton X-100, TX-100) micelles have been carried out. Rate of the reaction was found to be independent of the initial concentration of histidine (and histidine methyl ester) but was dependent on [Ninhydrin]. The SDS micelles had no effect on the rate of the reaction. In the presence of the CTAB micelles a small enhancement in the rate was observed. The profile showed that the increase in rate Ϫ [CTAB] [CTAB] increased the rate up to a maximum value and a further increase had a decreasing effect on the rate. The rate was enhanced by TX-100 also but, unlike CTAB micelles, TX-100 possessed a curve without peak for the profile. The following rate equation rate Ϫ [TX-100] was obeyed by the reaction in CTAB and TX-100 micelles:Values of k w , k m , and K S were evaluated and are reported herein.

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Calorimetric observations of the transition of spherical to rodlike micelles with solubilized organic additives

Cited by 96 publications

References 2 publications

Effect of Asymmetric Dimeric Zwitterionic Surfactants on Micellization Behavior of Amphiphilic Drugs

Effect of Asymmetric Dimeric Zwitterionic Surfactants on Micellization Behavior of Amphiphilic Drugs

Effects of various hydrocarbons on micellar growth

Kinetics of interaction of Histidine and Histidine Methyl Ester with Ninhydrin in micellar media

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